The present invention relates to a laser optical device for making the quantity of incident laser beams equal.
It is generally known to divide the laser beam and transmit the divided laser beams through optical fibers when the laser beam is used particularly for simultaneous processing of many points, for example.
An example of a conventional laser optical device will be described below with reference to FIG. 6.
FIG. 6 is a structural diagram of a conventional laser optical device, more specifically, a four-way laser optical device designed to divide and feed the laser beam into four optical fibers.
In FIG. 6, reference numerals represent respectively: 21 a laser oscillator; 22 a laser beam; 23-25 half mirrors; 26-28 total reflection mirrors; 29 laser beams after being divided; 30 an incidence lens; and 31 an optical fiber. These optical parts are held by a fixed tool. The laser beam 22 projected from the laser oscillator 21 is divided in two by the half mirror 23 disposed 45.degree. to the optical path. The divided laser beams are guided to the half mirror 24 and the total reflection mirror 26, respectively. In this manner, the laser beam 22 is eventually divided into four by the half mirrors 24, 25 and the total reflection mirrors 27, 28. Each diverged laser beam 29 is brought into the optical fiber 31 by the incidence lens 30 so as to be used for processing.
In the above-described arrangement, the intensity of laser beams after being diverged differs due to the reflecting characteristic of each mirror. A reflecting mirror having a multi-layered reflecting film generally has a variance in reflectivity of about .+-.5%. Therefore, when the laser beam is divided into four, the intensity can easily differ by an amount in the range of 20-30%.